Saadia Gaon

Saadia ben Yosef Gaon, also known as Said bin Yusuf al-Fayyumi, who lived from 892 to 942, was a prominent rabbi, gaon, Jewish philosopher and exegete active in the Abbasid Caliphate, and the first important rabbinic figure to write extensively in Judeo-Arabic, his extensive writings forming one of the foundations of Judeo-Arabic literature. Known for his works on Hebrew linguistics, halakha and Jewish philosophy, he was a student of the philosophical school known as Jewish Kalam, and in this capacity his work The Book of Beliefs and Opinions represents the first systematic attempt to integrate Jewish theology with components of ancient Greek philosophy. Saadia was also very active in opposition to Karaite Judaism in defense of Rabbinic Judaism.